Hi all Coming to Scala and would like to know, how...

# arrow

[zero_coding]

Hi all
Coming to Scala and would like to know, how to define the following tagless interface in Kotlin with Arrow:

trait GenderQuery[F[_]] {

  def findAll: F[Genders]

}

[raulraja]

While Arrow supports kind emulation via :

interface Foo<F> {
  fun foo(): Kind<F, Int>
}

[raulraja]

The best way in Kotlin to get tracked effects in this case would be

[raulraja]

interface Foo {
  suspend fun foo(): Int
}

[raulraja]

In its impl you can use in the next release the arrow fx coroutines lib currently available in snapshot for 0.11

[raulraja]

Which contains all you want out of IO but over suspend being more Kotlin diomatic and removing the callback indirections since Monads in this style are modeled as continuations

[raulraja]

https://arrow-kt.io/docs/next/fx/

[raulraja]

Kotlin even provides a suspend fun main which if you come from Haskell is the equivalent of main and in Scala is IOApp in cats or similar libraries

[raulraja]

suspend being a native impl of something similar to ContT can model and go from one monad to another without the use of higher kinded types

[raulraja]

more info here and soon in the docs when 0.11 is out https://twitter.com/raulraja/status/1291798081873338371